Edge grinding machine



me B, 1936, J, P, CROWLEY EDGE GRINDING MACHINE F'iled OCT.. 9, 1933 4 Sheets-Sheet 1 Ihwentor deaf/DH P Romff 5mm@ 341D, i136, J. p @RCM/LEY Zl@ EDGE GRNDING MACHINE,

Filed Oct. 9, 1933 4 Sheets-SheeTI 2 ISrmentor -JQJPH PFOWLEY.

me 3@ 11936 J. P. CRQWLEY EDGE GRINDNG MACHINE www 4 Sheets-Sheet 3 Filed Oct. 9, 1953 @/OEPH P Formen www,

EDGE GRINDING MACH INE l Filed Oct. 9, 1953 4 Sheets-Sheet 4 Imventor Q/OEPH P CPO wLEn Cttorneg Patented June 30, 1936 UNETED STATES PATENT OFFICE EDGE GRINDING MACHINE Application October 9, 1933, Serial No. 692,784

11 Claims.

The present invention relates broadly to improvements in grinding machines generally and more particularly to a machine for rounding and/or nishing the edges of sheets or plates of S glass and the like.

An important object of this invention resides in the provision of a grinding machine of simplined and inexpensive construction primarily designed for use in grinding the curved edges or ifi corners of sheets. or plates of glass which are to be employed as door or window lights in automotive vehicles, although it is of course in no way restricted to such use.

Another object of the invention is the provi- .5 sion of such a grinding machine of the above character which will round and nish the curved edges of the glass sheets or plates rapidly, accurately, and economically, and with a minimum leffort and attention on the part of the operator, whereby uniformly rounded edges with Well nished surfaces may be secured.

A further object of the invention is the provision of such a grinding machine of the above character capable of grinding curved edges of different contours and embodying a rotary grinding wheel, means mounted above said wheel for supporting a plurality of glass sheets to be ground, and means for rocking said supporting means to move the glass sheets backward and forward with the curved edges thereof to be ground over and in engagement with the grinding wheel, said supporting means being mounted in such a manner that it is capable of free vertical floating movement during the rocking thereof and depending upon the curvature of the edges being ground.

Other objects and advantages of the invention will become more apparent during the course cf the following description when taken in connection with the accompanying drawings.

In the drawings wherein like numerals are employed to designate like parts throughout the same,

Fig. 1 is a side elevation of a grinding machine V constructed in accordance with the present invention,

Fig. 2 is a vertical section therethrough taken substantially on line 2-2 of Fig. 1,

Fig.` 3 is a perspective view of the upper portion 59 of the machine showing particularly the means 55 and glass sheets during the grinding operation.

Fig. 7 is a view of one of the side members of the glass supporting means,

Fig. 8 is a detail section taken substantially on line 8-8 of Fig. 2,

Fig. 9 is a detail section taken substantially on line 9-9 of Fig. 1,

Fig. 10 is a similar section taken at the opposite side of the machine, and

Fig. 11 is a section taken substantially on line II-II of Fig. 3.

Referring now to the drawings and particularly to Fig. 2, the grinding machine herein provided includes a base I5 which is adapted to support the rotary grinding wheel I6 and the motor I 1 for driving the same, said motor being mounted upon the top of said base and the grinding wheel being arranged to one side thereof.

The grinding wheel I6 is keyed to one end of a horizontal shaft I8 and is provided in its periphery with a plurality of grooves f8 within which the edges of the glass sheets or plates to be ground are adapted to be received, as will be more clearly hereinafter apparent. The shaft I8 is rotatably supported in the spaced bearings and 2| carried by the base I5, said shaft pro- `jecting rearwardly beyond said base and journaled at its outer end in a bearing 22 carried by a gear case 23 suitably secured to the base f5. Keyed to the shaft I8 within gear case 23 is a relatively large gear 24 meshing with a relatively smaller gear 25 fixed to the shaft 26 of motor I1, said shaft being preferably journaled in a bearing 2l also carried by gear case 23. Upon operation of the motor I'I, it will be readily apparent that the shaft I8 will be driven through the intermeshing gears 24 and 25 to effect the positive rotation of the grinding wheel.

Arranged at the front of the base I5 is a receptacle 28 within which the grinding wheel I6 is received, said receptacle being adapted to' contain a suitable abrasive material within which the lower portion of the said wheel is adapted to be immersed in a manner well known in the art. The top of the receptacle 28 is provided with a slot 29 through which the upper portion of the grinding wheel projects. 'I'he receptacle is also preferably provided with a door 3B to permit access thereto and with a drain outlet 3| at one corner thereof.

The base I5 is slidably associated with the 50 receptacle 28 so that it can be moved vertically' relative thereto to either raise or lower the grinding wheel. To this end, the rear vertical wall 32 of the receptacle is formed with a vertical undercut channl or way 33 (Fig. 8) within 55 Y E Y 2,046,060

'a recess 48 and keyed to the upper end of screwj 31 within said recess is a relatively large gear.

4l meshing with a relatively smaller gear 42 keyed tothe lower Vend of a verticalV shaft 43 which passes downwardly through the said base. VExtending transversely through the upper end of' the shaft 43 is arod 44, constituting a handle which may be grasped by the operator to facilitate the turning of shaft t3. From the above, it will be seen that when it is desired to either Mraise or lower the base l and consequently the .grindng wheel i6, it is simply necessary for the operator to grasp the handle lll and ,turn the 'shaft 53 in the desired direction. YThe rotation of gear 42 rwill serve 'to eect'a corresponding rotation of gear 4| and upon rotation Yof gear 4|, the screw 31 will be threaded downwardly Y' or upwardly within the sleeve 38 to effect either vthe raising or lowering of the base and grinding wheel. c I The means for supporting the glass sheets to `be Vtreated comprises a box or holder designated Vin itsV entirety by the numeral 45, said holder being rmounted above the grinding wheel [I6 for tfree vertical and rocking movement as will be more fully hereinafter described. The work hold-V Ver- 55 comprises a pair of spaced vertical side Ymembers 46-.and 41 between which a plurality of glasssheets 48 to be ground are adapted to be received, said sheets being disposed in a vertical position Vand the said side members being so VVshaped that the curved edges or corners 49 of the glass sheets to be treated project therebeyond as clearly illustrated in Figs. l and 4 to 6, so

that upon rocking of the Work holder, the said p edges will be moved backward and forward over and in engagement with the grinding wheel.

A Arranged transversely between and carried by the side members 46 and 41 of the work holder,

adjacent the upper end thereof, are the three` horizontally aligned rollers 56, 5| and 52, while arranged transversely between said side members adjacent the opposite end thereof are the aligned rollers 53 and 54, said rollers beingradapted to receive the glass sheets 48 therebetween and to maintain them in proper position during the d grinding operation.

Each roller andV 5| comprises a Vhorizontal bolt 55 having its inner end extending through a vertical slot `56 in the sidemember 46 and being secured in place by a nut 51 threaded thereupon outwardly of said side member. VThe oppositeor outer end of the bolt 55 is provided with a head 58. Mounted upon the bolt 55 is a VVmetal bushing 59 carrying a sleeve 60 preferably c made of relatively soft rubber. This sleeve isk Y formed with a plurality of uniformly spaced annular flanges 6| which define therebetween a .plurality` of grooves 62 'within which the adja- I' l, cent edges of the glass rsheets d8 are adap-ted to be received, thegrooves 52 in the rollersl being inregistrywith the groovesV |9 in grinding wheel i6. The rubber flanges 6| are adapted to be strengthened by the provision of metal plates 63 Vembedded therein.

28 Vis The roller 52 is Vof the same construction and arrangement as rollers 50 and 5|, with the exception that the bolt 55 thereof also extends *Y through a vertical slo-t 64 in the side memberl'. Due to the provision of the slots 56 and 64, it will be readily apparent that the rollers 5U, 5| and 52 maybe moved toward Vor away from rollers 53 and 54 toaccommodate glass sheets of different sizes. The rollers 53 and 54 are likewise of the same construction as rollers 55, 5| `and 52 with the exception that they are not adjustablymounted, the bolts 55 thereof simply passing throughcircular openings in the side membersv 46 and 41.

Also positioned between and carried by the .side members 46 and 41 of the work holder are the rectangular metal plates 65 andV 66 respectively, each being secured in place by a plurality -of screws or the like 61. The plates 65 and 66 are disposed at substantially right angles relative to one another Vclosely adjacent different edges o f the side members and secured to the inner face of each is a relatively soft rubber pad 68 having a series of grooves 69 formed therein, said grooves being in registry with the grooves in the rollers 5B to 54 and being adapted to receive the adja-VVV cent edges of the glass sheets 48 therein.

Carried upon the outer surfaces of the side members 46 and 41 of the work holder and extending diagonally4 thereof are the plates 18 and 1| respectively to which are pivotally connected the inner ends of a pair of substantially horizontal parallel supporting arms 12 and 13 respectively, said arms being also freely mounted intermediate their ends Yupon a horizontal shaft 14 passing transversely through a blockV 15 supportked upon the top of the receptacle 23. The outer ends of the supporting arms 12 and 13 are bent inwardly towards one another as at 12 and 13 respectively, and suspended therefrom are a plurality. of weights 16, said `weights being hung upon an eye bolt 11 attached at its upper end to the supporting arms by a transverse pin 18.

The weights 16 are provided to counterbalance,v

the work holder 45 so'that the glass sheets being ground rest more or less freely upon the grinding wheel. However, by varying the weights, the pressure of` the glass sheetsupon the `grinding wheel may be increased or decreased as desired.

Fixed upon the shaft 14 at one end thereof, inwardly of supporting arm 12, is a bell crank lever 19 Vcomprising the two angularrly disposed portions or legs 88 and 8|. Pivoted to the outer end of leg 80 of the bell crank lever is one end of a substantially horizontal connecting rod 82 pivotallyV connected at its inner end to the plate 18 adjacent the lower end thereof beneath supporting arm 12. Keyed to the opposite end of shaft 14, inwardly of supporting arm 13, is a `lever 83 and pivotally connected thereto is one end of a substantially horizontal connecting rod 84 extending parallel with rodV 82 and being pivotally connected at its inner end to the plat 1| beneath supporting arm 13.

The inner end of each of the connecting rods 82 and 84 is formed withV an opening and Yis j adapted to have a pressed t over an annular cup-like member 85 (Fig. 9) freely mounted upon Y a pin 86 passing through the Vrespective plate 1E or 1|. Arranged within the cup member r85 and encircling the pin 86 isa ball ,bearing arrangement 81 which is provided to facilitate the Vpivotal action'ofV the connecting rod upon said pin. 'Ihe cup member 85 is covered `byra cap 88 which serves to hold the ball bearing arrange- 75 ment in place. Likewise, in order to facilitate the rocking movement of the work holder 45, the inner ends of the supporting arms 12 and 13 are similarly mounted upon pins 89 and 99 respectively (Figs. 9 and 10) passing transversely through the side members 46 and 41 and plates 19 and 1|, said pins being in horizontal alignment with one another and constituting the horizontal axis about which the work holder rocks. The plates 10 and 1| may also be secured to the side members 46 and 41 of the Work holder by rivets or the like 9| and 92 respectively.

Pivoted to the outer end of the leg 8| of the bell crank lever 19 is the upper end of a substantially vertical pitman 93 pivotally connected at its lower end to a crank 94 keyed to a horizontal s haft 95, said shaft being driven .from

'a motor 96 through a suitable chain and sprocket drive 91 and reduction gearing located in the housing 98. Upon rotation of the shaft 95, the pitman 93 will be given a substantially vertical upward and downward motion to effect the turning of the horizontal shaft 14 first in one direction and then the other to impart a substantially horizontal forward and backward motion to the connecting rods 82 and 84, it being of course understood that these rods work in unison. The reciprocation of` the connecting rods will cause the work holder 45 to be rocked upon the pins 99 and 99, thereby causing the glass sheets 48 to be moved backward and forward with the curved edges 49 thereof to be ground over and in engagement with the grinding wheel I6.

In the operation of the machine described above and when it is desired to grind the curved edges or corners 49 of a plurality of sheets of glass 48, the work holder 45 is first moved to the position illustrated in Figs. 1 and 4, at which time the pitman 93 is at substantially the extreme limit of its upward movement, while the connecting rods 82 and 84 are in retracted position. The glass sheets to be ground are then inserted horizontally into the outer open end of the holder between the upper rollers 50, 5| and 52 and the lower rollers 53 and 54, the upper Y vedges a of the said sheets being received within the grooves 52 in rollers 50, 5| and 52, while the'bottom edges b thereof are received within the grooves in rollers 53 and 54 and likewise within the grooves 69 formed in the rubber pad 68 carried by plate 6E. 'I'he glass sheets are moved inwardly until the inner edges c thereof abut the pad 68 carried by plate 65, being received within the grooves formed therein.

After the glass sheets have been properly positioned, the motor 96 is placed in operation to rotate the shaft 95 and draw the pitman 93 downwardly, this movement of the pitman causing the shaft 14 to be rocked in a counter-clockwise direction and imparting a forward movement to the connecting rods 82 and 84. This forward movement of the connecting rods will cause the work holder to be also rocked in a counter-clockwise direction upon the pins 89 and 90 and, during the turning of the said work holder, the curved edges 49 of the glass sheets 48 will of course be moved over and in engagement with the grinding wheel I6 being received within the grooves I9 thereof. The grinding wheel is being simultaneously driven preferably in the opposite direction. The work holder is turned approximately 90 degrees and at the limit of its backward movement will assume substantially the position illustrated in Fig. 6, at which time the glass sheets will be supported by the plate 65.

When the Work holder is in this position, the crank 94 has completed approximately one-half a revolution so that upon continued turning of the said crank, the pitman 93 will be started upwardly, thereby causing the shaft 14 to be rocked in a clockwise direction to effect backward movement of the connecting rods 82 and 84. 'I'his movement of the connecting rods will in turn cause the work holder 45 to be rocked upon the pins 89 and 99 in a clockwise direction to return it to its starting position shown in Figs. l, 3 and 4.

It will of course be readily apparent that upon rocking of the Work holder 45, the said holder will be permitted to simultaneously move freely vertically dep-ending upon the curvature of the sheet edges being ground. This is due to the fact that the supporting arms 12 and 13 are freely mounted upon shaft 14. The pins 89 and 99 may therefore be said to constitute a floating axis upon which the work holder may be rocked. Due to the above construction, curved edges of different contours can be readily and conveniently ground upon the machine and without necessitating any special adjustment to take care of each particular curve. This renders the machine capable of a wide use and permits the grinding of a plurality of sheets of glass rapidly, accurately, and economically, and with a minimum effort and attention on the part of the operator. While the machine has been referred to above as a grinding machine and also while it is primarily designed for this purpose, yet it f may be readily adapted for polishing the curved edges of the glass sheets by the substitution of a suitable polishing wheel for the grinding wheel I6.

As pointed out above, it is preferable that the weights 16 be such as to just counterbalance the work holder 45, so that the only pressure eX- erted upon the sheet edges being ground will be the weight of the sheets themselves. However, by removing some of the weights so that they are not sufficient to counterbalance the holder 45, the pressure upon the sheet edges being ground will be increased, whereas by adding additional weights, the pressure upon the sheet edges can be reduced.

It is desirable in the operation of the machine to effect a slight raising of the glass sheets at the completion of the movement of the work holder in either direction to lift the said sheets out of contact with the grinding wheel in order to prevent burning of the edges being ground. To this end, there is carried by the work holder 45, adjacent one corner thereof, a pair of freely rotatable rollers 99 and at the opposite diagonal corner a similar pair of rollers |00, each pair of rollers being mounted upon the opposite ends of a pin |0| passing transversely through the side members 46 and 41. The rollers are arranged outwardly of the said side members and are of such diameter that they project slightly beyond the edges thereof. Mounted upon the top of the receptacle 28, adjacent one end thereof, is a transversely arranged block |02, while mounted upon the top of said receptacle, adjacent the opposite end thereof, is a transverse plate |93.

Upon rocking of the work holder 45 to the left and when the said holder reaches the end of its movement in this direction, Athe rollers 9 9 vengaging block |02 will effect a `slight tilting .of

the said holder sufficient to lift the glassfsheets out of Vcontact with the grinding wheel. Likewise when the work holder is returned to its starting position and when it reaches the end oi its movement inthis direction, the rollers Iii@ engaging plate HB3 will serve toY lift the giass sheets out or" contactY with the grinding wheel as clearly illustrated in Figs. l and 4. Upon loading of the work holder preparatory to the grinding operation, the said holder is adapted to be in this position so that the curved edges 4d of the glass sheets will not contact with the grinding wheel as thesaid sheets are being placed in position. When the motor @il is piaced in operation to rock the work holder, the curved edges of the 'glass sheets will be gradually lowered toV engage the grinding wheel as illustrated inFig. 5.

Ordinarily, it will be found that one backwardY and forward rocking movement of Ythe work holder is suiilcient to effect the desired grinding of the glass sheets. '.'Lhereiore,l the present invention contemplates the provision of means for automatically shutting oi the motor 96 and stopping the rocking movement Vof the work holder atthe completion or" thegrinding operation. For

' the accomplishment ot this object, there is carried by the receptacle 23, a switch ltd (Fig. 1) connected circuit with and adapted to'control Vthe operation of motor Q5, said switch being provided with a control arm ide having a roller i536.

its starting position shown in Fig. 4 to complete n the grinding cycle, the tripV member m1 engaging the roller H36 will force the control arm les downwardly to open the switch iii/3, thereby breaking the circuit through the motor 96 and stopping the movement of the work holder.V The trip member itil, however, is not adapted to actuate the switch 694 until after the rollers mi! engaging plate ltiiirhave caused the glass sheets to be lifted out oi contact with the grinding wheel.

It is toV be understood that the form of the in- Y vention herewith shown and described is to be taken as the preferred embodimenty of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the Vscope of the subjoined claims.

I claim:

` l. Ina machine for grinding the curved edge of a glass sheet or plate, a rotary grinding wheel positionedvto rotate aboutra substantially horizontal axis, means arranged above saidk wheel for supporting theoglas's sheet to be ground on edge in a substantially vertical position, means for rocking said supporting means and sheet carried thereby to' move the curved edgejcf the sheet to be ground over and in engagement with said grinding wheel, means for pivotally mounting the supporting means upon a flo-ating axis so that it isvcapable of free vertical iioating Y movement during the rocking thereof, and means for counterbalaneing said supporting means.

2. In a machine for simultaneously grinding to rotate about a substantially horizontalaxis,

Vmeans for supporting the glass Vsheets to be ground onedge in a substantially vertical posirocking Vmovement includingan arm ypivotally i connected theretol andVV forming an axis kabout which the box is adapted to be rocked, and meansY for rocking the said Vbox aboutsaid axis to move the curved edges of the glass sheets to be ground ver and in engagement with said grinding wheel. 3. In a machine` for simultaneously grinding the curved edges of a piurality of glass sheets or plates, a rotary grinding wheel positioned to rotate about a substantially horizontally axis, means for supporting `the glass sheets to be ground on edge a substantially vertical position embodying a box arranged above said wheel and including spaced vertical side members betweenwhich the sheets are received, means carried byand arranged between said side members for maintaining the sheets in position during` grinding, means for mounting said boxY for free vertical and rocking movement including an arm 'i" pivotally connected at one end thereto and forming an axis about which the boxk is adapted to be rocked, said armgbeing also'pivotally mounted adjacent its opposite end to turn freely about a xed axis, and means for rockingr said box about said first-mentioned axis to rnc-ve kthe while simultaneouslyallowing said box to move n bodily vertically about'said xed axis.

SeV

4. In a machine for simultaneously grindingV the curved edges of a plurality of glass sheets or plates, a rotary grinding wheel positioned to rotate about a substantially horizontal axis,

meansv for supporting the glass sheets to be,

ground on edge in a substantially vertical po- Y at one end thereto and forming a horizontal-- axis about which the box is adapted to be rocked, said arm being also pivotally mounted intermediate its ends to turn freely about a xec.

horizontal axis, means for rocking said box about ,said first-mentioned axis to move the curved: edges or" the glass sheets to be ground over and in engagement with said grinding wheel while simultaneously allowing said box to move bodily vertically about said ixed axis, and means carried byvsaid arm outwardly of said fixed axis for counterbalancing saidr box.

5..In a machine for simultaneously grinding the curved edges of a plurality ofglass sheets or plates, a rotary grin-ding wheel positioned to rotate about a substantially Yhorizontal axis,

means Vfor supporting the glass sheetsto be ground on edge inV a substantially vertical position embodying a box arranged above said wheel and including spaced vertical side members between which the sheets are received, meansY carried by and arranged between said side members for maintaining the sheets in position during i vertical an-d'rocking movement including a sub- Y grinding, means for mounting said box for free f stantially horizontal arm pivotally connected at7r5 lll lill

Hill* WHW one end thereto and forming a horizontal axis about which the box is adapted to be rocked, said arm being also pivotally mounted adjacent its opposite end to turn freely about a xed horizontal axis, and means for rocking said box about said first-mentioned axis to move the curved edges of theY glass sheets to be ground over and in engagement with said grinding wheel including a substantially horizontal rod pivotally connected at one end to said box, a motor, and operative connections between said motor and the opposite end of said rod to eifect forward and backward movement of sai-d rod upon operation of said motor.

6. In a machine for simultaneously grinding the curved edges of a plurality of glass sheets or plates, a rotary grinding wheel positioned to rotate about a substantially horizontal axis, means for supporting the glass sheets to be ground on edge in a substantially vertical position embodying a box arranged above said Wheel and including spaced vertical side members between which the sheets are receivedi, means carried by and arranged between said side members for maintaining the sheets in position during grinding, means for mounting said box for free vertical and rocking movement including a substantially horizontal arm pivotally connected at one end thereto and forming a horizontal axis about which the box is adapted to be rocked, said arm being also pivotally mounted intermediate its ends to turn freely about a xed horizontal axis, means for rocking sai-d box about said first-mentioned axis to move the curved edges of the glass sheets to be ground over and in engagement with said grinding wheel including a substantially horizontal rod pivotally connected at one end to said box, a motor, and operative connections between said motor and the opposite end of said rod to effect forward and backward movement of said rod upon operation of said motor, and means carried by said arm outwardly of said fixed axis for counterbalancing said box.

7. In a machine for simultaneously grinding the curved edges of a plurality of glass sheets or plates, a rotary grinding wheel positioned to rotate about a substantially horizontal axis and having a plurality of grooves formed in the periphery thereof, means for supporting the glass sheets to be ground on edge in a substantially vertical position including a box arranged above said wheel and comprising spaced vertical side members between which said sheets are received, a plurality of rollers carried by and arranged between said side members for maintaining the glass sheets in position during grinding, said rollers having grooves in registry with the grooves in the grinding wheel and within which the edges of the sheets are received, a pair of stationary mats also carried by and arranged between the side members and having grooves in registry with the grooves in the grinding wheel and rollers and within which the edges of the sheets are received, said mats being arranged at substantially right angles relative to one another, means for mounting said box for free vertical and rocking movement, and means for rocking the box to move the glass sheets back and forth with the curved edges thereof to be ground over and in engagement with said grinding wheel.

8. In a machine for grinding the longitudinally curved edge of a glass sheet or plate, a rotary grinding Wheel positioned to rotate about a substantially horizontal axis, means mounted above said wheel for supporting the glass sheet to be ground on edge in a substantially vertical position, means for rocking said supporting means and sheet carried thereby back and forth in the plane of said sheet to move the longitudinally curved edge thereof to be ground over and in engagement with said grinding wheel, means for pivotally mounting the supporting means upon a floating axis so that it is capable of free vertical floating movement during the rocking thereof depending upon the curvature of the said edge being ground, and means for counterbalancing said supporting means.

9. In a machine for grinding the curved edge of a glass sheet or plate, a rotary grinding wheel positioned to rotate about a substantially horizontal axis, means mounted above said wheel for supporting the glass sheet to be ground on edge in a substantially vertical position, an arm to which the supporting means is pivoted on a horizontal axis for rocking movement to carry the curved edge of the glass sheet over the grinding wheel, a pivotal support for the arm at one side of the axis of rotation of the grinding wheel about which the arm swings freely during the grinding operation, and means for rocking the sheet supporting means.

1G. In a machine for grinding the curved edge of a glass sheet or plate, a rotary grinding wheel positioned to rotate about a substantially horizontal axis, means mounted above said wheel for supporting the glass sheet to be ground on edge in a substantially vertical position, an arm to which the supporting means is.pivoted on a horizontal axis for rocking movement to carry the curved edge of the glass sheet over the grinding wheel, a pivotal support for the arm at one side of the axis of rotation of the grinding wheel about which the arm swings freely during the grinding operation, means for rocking the sheet supporting means, and means for counterbalancing said supporting means.

11. In a machine for grinding the curved edge of a glass sheet or plate, a rotary grinding wheel positioned to rotate about a substantially horizontal axis, means mounted above said wheel for supporting the glass sheet to be ground on edge in a substantially vertical position, an arm to one end of which the supporting means is pivoted on a horizontal axis for rocking movement to carry the curved edge of the glass sheet over the grinding wheel, said arm being also pivotally mounted adjacent its opposite end to swing freely about a xed axis during the grinding operation, means for rocking the sheet supporting means, and means associated with the outer end of said arm for counterbalancing said supporting means.

JOSEPH P. CROWLEY. 

